Noble gases are usually only observed when they have been implanted in materials - such as when sputtering using an ion beam. Relevant binding energies below [1].
Ne 1s: 861.6 - 863.4 eV
Ne 2s: ~ 41 eV
Ar 2p3/2: 240.3 - 241.9 eV
Ar 2p3/2 - 2p1/2 splitting is 2.12 eV
Ar 2s: ~ 320 eV
Ar 3s: ~ 24 eV
Kr 3d5/2: ~ 87 eV
Kr 3d5/2-3d3/2 splitting is 1.23 eV
Kr 3p3/2: ~ 208 eV
Kr 3p1/2: ~ 216 eV
Kr 4s: ~ 21 eV
Xe 3d5/2: 668.9 - 674.1 eV
Xe 3d5/2 - 3d3/2 splitting is 12.67 eV
Xe 3p3/2: ~ 943 eV
Xe 3p1/2: ~ 996 eV
Note that MNN Auger structure overlaps the 3p3/2 peak (when using an Al X-ray source)
Xe 4d 5/2: ~ 61 eV
Xe 4d 3/2: ~ 63 eV
Xe 4p: ~ 139 eV
Xe 4s: ~ 207 eV
Xe 3s: ~ 1141 eV
Reference:
[1] J.F. Moulder, W.F. Stickle, P.E. Sobol, K.D. Bomben, Handbook of X-ray Photoelectron Spectroscopy, Perkin-Elmer Corp, Eden Prairie, MN, 1992.
Gold
The Au 4f7/2 ISO standard binding energy for metallic gold used for calibration is 83.96 eV (for monochromatic Al K(alpha) X-rays).
Typical fitting parameters for pure sputter cleaned gold (10 eV pass energy) include:
FWHM ~ 0.59 eV, GL(86) peak-shape
Au 4f7/2 - Au 4f5/2 splitting ~ 3.67 eV
 |
| Au 4f XPS spectrum of sputtered cleaned gold. |
The Use and Misuse of Curve Fitting in the Analysis of Core X-ray Photoelectron Spectroscopic Data
Peter Sherwood at the University of Washington has recently published a very good review article [1] that goes through many of the issues and pitfalls associated with achieving meaningful results from curve fitting XPS spectra. It also includes a useful tutorial section that uses the W 4f spectrum of oxidized tungsten to illustrate the methods outlined in the paper. A good starting point read for those who are getting into curve-fitting of XPS spectra (and for those needing a refresher!).
Reference:
[1] Peter M.A. Sherwood, The use and misuse of curve fitting in the analysis of core X‐ray photoelectron spectroscopic data, Surf. Interface Anal. 51 (2019) 589-610.
Reference:
[1] Peter M.A. Sherwood, The use and misuse of curve fitting in the analysis of core X‐ray photoelectron spectroscopic data, Surf. Interface Anal. 51 (2019) 589-610.
Advanced Analysis of Copper X-ray Photoelectron Spectra
This recent paper [1] builds upon and extends previously published X-ray photoelectron spectroscopy (XPS) curve-fitting and data analysis procedures [2,3] for a wide range of copper containing species. Steps undertaken include: 1) an examination of existing Cu 2p3/2 main peak and Cu 2p3/2 - Cu L3M4,5M4,5 Auger parameter literature data, 2) analysis of a series of quality standard samples, 3) curve-fitting procedures for both the Cu 2p3/2 and the Cu L3M4,5M4,5 spectra (as well as associated anions), 4) calculations that determine the amount of Cu(II) species in a mixed oxidation state system, 5) calculations and necessary data for thin film mixed oxide/hydroxide thickness measurements and 6) a presentation of literature and standard sample values in a Wagner (chemical state) plot.
Some examples of the extensive datasets and spectra available in this paper are presented below.
Reference:
[1] M.C. Biesinger, Advanced Analysis of Copper X-ray Photoelectron (XPS) Spectra, Surf. Interface Anal. 49 (2017) 1325-1334.
[2] M.C. Biesinger, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2010) 887-898.
[3] M.C. Biesinger, B.R. Hart, R. Polack, B.A. Kobe, R.St.C. Smart, Miner. Eng. 20 (2007) 152.
Some examples of the extensive datasets and spectra available in this paper are presented below.
 |
| Cu 2p3/2 spectra of various Cu(II) species. |
 |
| Cu L3M4,5M4,5 spectra for (left) Cu(0), Cu(I) species, mineral samples, and (right) Cu(II) species. |
 |
| Curve-fitted Cu L3M4,5M4,5 spectrum of wrought copper sample submerged in an Ar aerated 3M NaCl solution for 30 days. Curve-fitting results suggest 22 % Cu(0), 65 % Cu2O and 13% Cu2S. |
 |
| Cu 2p3/2 - Cu L3M4,5M4,5 Wagner (chemical state) plot with literature and standard sample data. |
 |
| Cu 2p3/2 and Cu 2p3/2 - Cu L3M4,5M4,5 Auger parameter literature values from Cu species |
 |
|
Cu 2p3/2 (main peak only) and Cu 2p3/2 - Cu L3M4,5M4,5 Auger parameter values from standard samples (20 eV pass energy). a) 932.63 eV for non-monochromatic Al X-ray source, 932.62 eV for monochromatic Al K(alpha) X-ray source b) Note that this value is specified for the Kratos instruments used in this work. Other instruments may not have this accuracy. This will also not apply for Cu(0) in a non-conductive environment where calibration to other peaks are needed (e.g. adventitious carbon C 1s which has an error of 0.1 to 0.2 eV associated with it). |
[1] M.C. Biesinger, Advanced Analysis of Copper X-ray Photoelectron (XPS) Spectra, Surf. Interface Anal. 49 (2017) 1325-1334.
[2] M.C. Biesinger, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2010) 887-898.
[3] M.C. Biesinger, B.R. Hart, R. Polack, B.A. Kobe, R.St.C. Smart, Miner. Eng. 20 (2007) 152.
Germanium
 |
| Ge 3d binding energy values. |
 |
| Ge 3p3/2 binding energy values. |
 |
| Ge 3d - L3M45M45 Auger Parameter values. |
Notes:
Ge 3d5/2-3/2 splitting is 0.59 eV
Ge 3p3/2-1/2 splitting is 4.18 eV
Ge 3s: 181 eV
Ge 2p3/2: 1217 eV
Ge 2p1/2: 1248 eV
 |
| XPS survey spectrum of germanium (Al K(alpha) X-ray source). |
Calcium
 |
| Ca 2p3/2 binding energy values. |
Ca 2p3/2-2p1/2 splitting is 3.55 eV (for CaCO3).
In survey spectra of samples where magnesium is also present there can be an overlap of the Ca 2p region with Mg KLL structure. In these cases it is better to use the Ca 2s peak for quantification.
Standards taken at Surface Science Western.
CaPO4
Ca 2p3/2: 347.3 eV
P 2p3/2: 133.2 eV
P 2s: 190.7 eV
O 1s: 531.1 eV
CaCO3
Ca 2p3/2: 346.5-347.0 eV
O 1s: 531.1 eV
C 1s (CO3): 289.2-289.4 eV
CaSO4
Ca 2p3/2: 348.3 eV
O 1s: 532.5 eV
S 2p3/2: 169.6 eV
Gypsum (CaSO4 . 2H2O)
Ca 2p3/2: 348.1-348-3 eV
O 1s (SO4): 532.1- 532.4 eV; O 1s (H2O) 533.4 - 533.5 eV
S 2p3/2: 169.3eV
 |
| Ca 2p spectrum of CaSO4. |
Manganese
Manganese, having six stable oxidation states (0, II, III, IV, VI and VIII), three oxidation states with significant multiplet splitting (II, III, IV), one oxidation state with less defined splitting or broadening (VI), and overlapping binding energy ranges for these multiplet splitting structures, presents a serious challenge for both qualitative and quantitative analysis.
Nesbitt and Banerjee use curve fitting of Mn 2p3/2 spectra to interpret MnO2 precipitation[1] and reactions on birnessite (MnO1.7(OH)0.25 or MnO1.95) mineral surfaces[2,3,4]. These papers provide excellent detail of FWHM values, multiplet splitting separations and peak weightings for easy reproduction of their curve fitting procedure. Binding energies are quoted uncorrected for charging and the measured adventitious C 1s charge reference of 284.24 eV can only be found in one paper[2]. Fitting parameters are based on standard spectra of MnO, natural manganite (MnOOH) and synthetic birnessite films (MnO2) recorded on a Surface Science Laboratories SSX-100 X-ray photoelectron spectrometer equipped with a monochromatic Al Kα X-ray source. These fittings, with binding energies now corrected to adventitious C 1s at 284.8 eV (original data were shown uncorrected), are presented in Table 1[5]. Also presented are peak parameters for a sputtered cleaned metal surface taken using the same instrument and analysis conditions.
Table 1. Mn 2p3/2 spectral fitting parameters compiled from references [1, 2, 3 and 4]: binding energy (eV), percentage of total area, FWHM value (eV) for each pass energy, and spectral component separation (eV). Metal peak parameters were from spectra taken using the same Surface Science Laboratories SSX-100 X-ray photoelectron spectrometer and conditions as the above references.
Fitting parameters for recent spectra [5] of the metal, and powder standards MnO, Mn2O3, MnO2, K2MnO4 and KMnO4, are presented in Table 2 with spectra for these standards given in Figures 1 and 2. Spectra and fittings from in-vacuum fractured minerals specimens of manganite (MnOOH) and pyrolusite (MnO2) are also presented (Figure 3 and Table 2). These fittings are based on the parameters presented in Table 1 and modified as needed.
Table 2. Mn 2p3/2 spectral fitting parameters: binding energy (eV), percentage of total area, FWHM value (eV) for each pass energy, and spectral component separation (eV) [5].
Figure 1. Mn 2p spectra for (bottom) Mn metal, (middle) MnO, (top) Mn2O3 [5].
Figure 2. Mn 2p spectra for (bottom) MnO2, (middle) K2MnO4, and (top) KMnO4 [5].
Figure 3. Mn 2p spectra for (bottom) manganite (MnOOH) and (top) pyrolusite (MnO2) [5].
References:
[1] H.W. Nesbitt, D. Banerjee, Am. Mineral. 83 (1998) 305.
[2] D. Banerjee, H.W. Nesbitt, Geochim. Cosmochim. Acta 63 (1999) 3025.
[3] D. Banerjee, H.W. Nesbitt, Geochim. Cosmochim. Acta 63 (1999) 1671.
[4] D. Banerjee, H.W. Nesbitt, Geochim. Cosmochim. Acta 65 (2001) 1703.
[5] M.C. Biesinger, B.P. Payne, A.P. Grosvenor, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2011) 2717.
Addendum:
As recent article from Eugene Ilton[6] uses a similar approach to that above. Ilton uses high quality 2p, 3p and 3s peak-shapes from a variety of species (rancieite (Mn(IV)), manganite (Mn(III)) and MnO (Mn(II))) to investigate unknown samples. A test of the use of the Mn 3s splitting values as a means to determine oxidation state shows it to be not of great value (i.e. doubt is cast on its usefulness).
Reference:
[6] E.S. Ilton, J.E. Post, P.J. Heaney, F.T. Ling, Appl. Surf. Sci. 366 (2016) 475.
Nesbitt and Banerjee use curve fitting of Mn 2p3/2 spectra to interpret MnO2 precipitation[1] and reactions on birnessite (MnO1.7(OH)0.25 or MnO1.95) mineral surfaces[2,3,4]. These papers provide excellent detail of FWHM values, multiplet splitting separations and peak weightings for easy reproduction of their curve fitting procedure. Binding energies are quoted uncorrected for charging and the measured adventitious C 1s charge reference of 284.24 eV can only be found in one paper[2]. Fitting parameters are based on standard spectra of MnO, natural manganite (MnOOH) and synthetic birnessite films (MnO2) recorded on a Surface Science Laboratories SSX-100 X-ray photoelectron spectrometer equipped with a monochromatic Al Kα X-ray source. These fittings, with binding energies now corrected to adventitious C 1s at 284.8 eV (original data were shown uncorrected), are presented in Table 1[5]. Also presented are peak parameters for a sputtered cleaned metal surface taken using the same instrument and analysis conditions.
Fitting parameters for recent spectra [5] of the metal, and powder standards MnO, Mn2O3, MnO2, K2MnO4 and KMnO4, are presented in Table 2 with spectra for these standards given in Figures 1 and 2. Spectra and fittings from in-vacuum fractured minerals specimens of manganite (MnOOH) and pyrolusite (MnO2) are also presented (Figure 3 and Table 2). These fittings are based on the parameters presented in Table 1 and modified as needed.
References:
[1] H.W. Nesbitt, D. Banerjee, Am. Mineral. 83 (1998) 305.
[2] D. Banerjee, H.W. Nesbitt, Geochim. Cosmochim. Acta 63 (1999) 3025.
[3] D. Banerjee, H.W. Nesbitt, Geochim. Cosmochim. Acta 63 (1999) 1671.
[4] D. Banerjee, H.W. Nesbitt, Geochim. Cosmochim. Acta 65 (2001) 1703.
[5] M.C. Biesinger, B.P. Payne, A.P. Grosvenor, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2011) 2717.
Addendum:
As recent article from Eugene Ilton[6] uses a similar approach to that above. Ilton uses high quality 2p, 3p and 3s peak-shapes from a variety of species (rancieite (Mn(IV)), manganite (Mn(III)) and MnO (Mn(II))) to investigate unknown samples. A test of the use of the Mn 3s splitting values as a means to determine oxidation state shows it to be not of great value (i.e. doubt is cast on its usefulness).
Reference:
[6] E.S. Ilton, J.E. Post, P.J. Heaney, F.T. Ling, Appl. Surf. Sci. 366 (2016) 475.
Antimony
 |
| Sb 3d5/2 binding energy values [1]. |
 |
| Curve-fitted Sb 3d and overlapping O 1s XPS spectrum. |
Sb 3d5/2 -3d3/2 doublet separation: 9.34 eV [2].
Sb 3p3/2: 767 eV
Sb 2p1/2: 813 eV
Sb 3s: 944 eV
Sb 4d: 33 eV
Sb 4p: 99 eV
Sb 4s: 153 eV
Notes:
A) Sb 3d5/2 overlaps with the O 1s spectrum. One needs to fit and constrain the Sb 3d5/2 and Sb 3d3/2 peaks using the 3d3/2 peaks as a guide. Remaining area in the 3d5/2 area will be due to O 1s signal (see spectrum above).
B) Sb2O3 standard samples has Sb 3d5/2 at 530.1 to 530.3 eV. Sb2O5 standard sample is at 530.9 eV [3].
C) Sb2S3 standard sample (Stibnite mineral sample) has Sb 3d5/2 peak at 529.6 eV and S 2p3/2 at 161.2 eV [3].
D) KSbO3 standard sample has Sb 3d5/2 peak at 530.7 eV and K 2p3/2 at 292.8 eV [3].
References:
[1] C.D. Wagner, A.V. Naumkin, A. Kraut-Vass, J.W. Allison, C.J. Powell, J.R.Jr. Rumble, NIST Standard Reference Database 20, Version 3.4 (web version) (http:/srdata.nist.gov/xps/) 2003.
[2] J.F. Moulder, W.F. Stickle, P.E. Sobol, K.D. Bomben, Handbook of X-ray Photoelectron Spectroscopy, Perkin-Elmer Corp., Eden Prairie, MN, 1992.
[3] M.C. Biesinger, unpublished results (2015).
Palladium
 |
| Pd 3d5/2 binding energy values [1]. |
Pd 3d5/2 - Pd 3d3/2 splitting: 5.31 +/- 0.12 eV (ave. of 8 Ref.), [2] specifies a splitting of 5.26 eV. Reference spectrum of the metal shows a splitting of 5.29 eV (see spectrum below).
Pd 3p3/2: 533 eV
Pd 3p1/2: 560 eV
Pd 3s: 671 eV
Pd 4p: 52 eV
Pd 4s: 88 eV
Notes:
A) PdO is reduced relatively rapidly by X-rays. Take steps to minimize X-ray exposure during acquisition.
B) Some references quote B.E. values for PdO2, however PdO is the only well characterized oxide of palladium.
C) For a sputter cleaned Pd metal surface a Pd 3d5/2 lineshape of LA(1.9,7,2) and FWHM of 0.68 eV (10 eV pass energy) or 0.71 eV (20 eV pass energy) was found.
 |
| Pd 3d spectrum of sputter cleaned Pd metal. |
[1] C.D. Wagner, A.V. Naumkin, A. Kraut-Vass, J.W. Allison, C.J. Powell, J.R.Jr. Rumble, NIST
Standard Reference Database 20, Version 3.4 (web version) (http:/srdata.nist.gov/xps/) 2003.
[2] J.F. Moulder, W.F. Stickle, P.E. Sobol, K.D. Bomben, Handbook of X-ray Photoelectron Spectroscopy, Perkin-Elmer Corp., Eden Prairie, MN, 1992.
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